A plumbing fixture is known with an electrically powered control unit that can regulate the rate and/or temperature of the water flowing through the unit. For instance a mixing faucet can have manual temperature selection but an electrically powered on/off function that is tripped by means of an infrared or proximity sensor in the faucet. Thus as the user puts his or her hands under the spout, the valve is automatically opened to dispense water at the desired temperature, and when the hands are removed the water flow is cut off.
Such a system typically is powered by a heavy-duty lithium battery that has a relatively long service life. Nonetheless, once the battery is exhausted, the faucet does not work and it takes a relatively competent person to replace it. A module of the faucet must be pulled out and the battery taken out and replaced with a new one. This job is perfectly feasible for someone who is fairly handy, but imposing if not impossible for many.